As a reaction system for a Fischer-Tropsch synthesis reaction (hereinafter called FT synthesis reaction) that generates a hydrocarbon compound and water by catalytic reaction from a synthesis gas which is mainly composed of hydrogen and carbon monoxide, a bubble column type slurry bed FT synthesis reaction system that carries out an FT synthesis reaction by introducing a synthesis gas into a slurry in which solid catalyst particles are suspended in a liquid hydrocarbon is available (for example, refer to Patent Documents 1 and 2 as mentioned below). Further, a hydrocarbon compound synthesized by the FT synthesis reaction is mainly utilized as a raw material for liquid fuel products such as naphtha (rough gasoline), kerosene and gas oil.
Further, as this bubble column type slurry bed FT synthesis reaction system, there is an external circulation type FT synthesis reaction system including a reactor main body which accommodates slurry, and a gas-supplying section which introduces synthesis gas into the bottom of the reactor main body, and an external circulation section which makes the catalyst slurry including a hydrocarbon compound synthesized within the reactor main body flow out from the reactor main body, separates the hydrocarbon compound from the catalyst slurry, and returns the catalyst slurry to the reactor main body again. In Patent Documents 1 and 2, a pump is used for the flow of the slurry through an external circulation section. However, if the pump, etc. is used, the performance of catalyst particles may degrade due to attrition.
Accordingly, in this configuration, when the synthesis gas introduced into the reactor main body ascends through the slurry, an upward flow (airlift) is generated in the reactor main body. Therefore, the circulating flow of the slurry is generated in the reactor main body in its vertical direction. Also, the flow of the slurry through the external circulation section is generated with the circulating flow of the slurry within the reactor main body.    PATENT DOCUMENT 1: US Patent Application, First Publication No. 2003/0018089    PATENT DOCUMENT 2: US Patent Application, First Publication No. 2007/0014703